Mobile communication networks transmit data to one or more devices using radio frequency (RF) signals. The RF signals are radiated from a transmission antenna, generally located at a cellular tower or transmission site. In order to generate the RF signal the transmission antenna is driven by an analog signal. The signal to be transmitted may be communicated to the transmission site as a digital signal. An analog signal is synthesized from the digital signal and amplified in order to provide the signal for driving the transmission antenna. Receiving the transmission data as a digital signal requires equipment at the transmission site to convert the signal to an analog signal. This digital-to-analog conversion equipment is typically located in close proximity to the transmission antenna in order to prevent or reduce signal degradation by transmitting an analog signal over a length of cable.
It may be desirable to reduce the equipment necessary at the transmission antenna. Accordingly, the equipment that creates the analog signal, and the transmission antenna, may be at different locations, with cabling between the locations. It is challenging to carry an analog signal over electrical cabling, due to the large weight and poor signal integrity of electrical cables. Thus, the analog signal may be carried on an optical fiber. This and similar arrangements are known as a radio-over-fiber (RoF) system or an RF-over-fiber system.
It may be desirable to provide additional, alternative and/or improved techniques for providing an analog signal to be carried over an optical fiber.